Pansies offer long lasting color in fall

At this time of year, the parking lot of the local greenhouse I worked at in St. Louis County would be covered in chrysanthemums.

Patrick Greenwald

Patrick GreenwaldMU-Extension Horticulture SpecialistAt this time of year, the parking lot of the local greenhouse I worked at in St. Louis County would be covered in chrysanthemums. Many a time I was responsible for pinching back hundreds of young chrysanthemum plants in May and early June, delaying their flowering and stimulating a dense branching of their flowering stems. It's no wonder, after years of stooping over hundreds of "mums" in late spring, that I prefer to break away from planting the most popular fall flowering ornamental, and plant others, such as pansies.Last October, I decided to plant a patch of pansies in a sunny spot in my woodland garden. The plants bloomed profusely until early December, protected by the surrounding woodland and fresh layer of newly fallen oak leaves.I was amazed at the lasting color the pansies brought to the dreary late autumn garden landscape. With the protection of mulch, the pansies bloomed again the following spring before diminishing with the onset of late spring warm temperatures. Pansies (Viola X wittrockiana)Now is the perfect time to plant pansies in your home garden. The hybrid pansy Viola X wittrockian, has long been cultivated in Europe since the early 1800s. They are winter annuals, and transplants are best planted in either early fall or early spring.In the spring, they will bloom until the temperatures get too hot and they begin to diminish. In the fall, already blooming/budding pansy transplants purchased from a local greenhouse will continually bloom until the temperatures get too cold and the ground eventually freezes solid. Since often our winters are mild, many times they will persist and produce a second display of flowers in early spring. When planting pansies in your home garden choose a site which is well drained and receives plenty of sunlight. Pansies can take moderate shade but bloom better in higher amounts of light. This is a great time of year to incorporate fully composted organic matter into your soil, which can serve a dual purpose of improving the soil structure for the pansy roots and preparing the garden for the spring planting season.Since compost typically has a more neutral pH, a soil amendment such as peat moss which is acidic could help loosen the soil without raising the pH.It is best to transplant pansies that have not been stressed in their pots and are smaller in size. For proper nutrient uptake of pansy roots, it is best to plant pansies on a site where the soil pH is acidic (5.4-5-8 pH). When establishing the transplants in September, they should be well-watered, and as they grow, the soil should not be allowed to dry completely. Keep in mind that as temperatures cool, watering needs will be less. In the southeastern U.S., pansies are a common fall bedding plant because the moderate winter temperatures allow them to bloom all winter. After planting, the University of Georgia Cooperative Extension recommends watering the plants with a nitrate-based water soluble fertilizer.For best results, mulch the pansy bed with straw or lightweight mulch when temperatures are consistently below freezing to prevent cold, drying winds from damaging the plants in winter. Last season I allowed the pansies to be covered in a few inches of leaf litter in late October, which seemed to work well in overwintering them until the spring season.Since the common hybrid pansy has been in cultivation so long, consumers have many choices of colors and color patterns to choose from. I prefer the classic blue and yellow varieties with a dark blotches in the center of the flower. For healthy plants, it is best not to overcrowd pansies, planting them no closer than 6 inches apart, as they can grow 8-10 inches tall and wide.The autumn ornamental planting season offers great possibilities to create a cool season flower garden which persists until mid- to late-fall. If you are tired of planting "mums," try planting a few pansies.Even if we have a harsh winter, which can cause the plants to diminish, you will not be disappointed in their ever blooming display throughout this coming fall.